1. Field of the Invention
The present invention relates to a wireless sensor network of sensor nodes and zones. More particularly, the present invention relates to a data aggregation apparatus and method using the apparatus which can easily recognize location information of all sensor nodes, and which can apply the location information to expand a network by aggregating data using zone scheduling on a wireless sensor network.
2. Description of Related Art
A wireless sensor network refers to a network (e.g., a wireless mesh network) including tens to several thousands of sensor nodes capable of communicating with each other using a radio frequency (RF) to sense physical space, the network being spread over a wide area. Due to development of a sensor technique, technology for a microelectromechanical system (MEMS) can be connected via a wireless network and is embracing low power electronics engineering technology, low power RF planning technology, and the like. As a result, miniature sensor nodes are being developed that operate at low power levels and have low costs.
A large number of sensor nodes are formed within the same domain or a similar domain of interest to form a wireless sensor network, and may be applied to various applications such as health management, military, home networking, environmental monitoring, factory management, and disaster management. The locations of the sensor nodes are not required to be predetermined in the wireless sensor network, therefore the sensor nodes may be arbitrarily located and may be applied to areas difficult to access, such as in disaster rescue areas.
When a security network is configured in a wireless sensor network, a sensor surveilling burglar's movement and a sensor sensing open/close status of an entrance door are used as the sensor nodes, and the sensor nodes sense the burglar's movement or the open/close status of the entrance door, and the sensor nodes wirelessly transmit the burglar's movement or the open/close status of the entrance door to a control apparatus.
Protocols in the sensor network have an ability of self-organizing, and sensor nodes operate by cooperating with each other.
In the wireless sensor network, a large number of sensor nodes may be located in the region of interest without a predetermined arrangement. The wireless sensor network has an advantage in that overall operation of a network is not affected when a predetermined sensor node fails and no longer functions since neighboring sensor nodes sense similar information.
However, the wireless sensor network has drawbacks of low speed wireless media transmission, frequent transmission errors, a limited power supply, and difficulty in replacing the sensor nodes due to arbitrary distribution of the sensor nodes. Since a lifetime of the wireless sensor network is determined by a lifetime of a battery of the sensor nodes, an operation lifetime is required to be extended as long as possible to extend the lifetime of the the wireless sensor network. Thus, protocols for the wireless sensor network are needed to improve the lifetime of an entire system and to cope with dynamic changes of the wireless sensor network by distributing energy consumption within the entire network.
Accordingly, there is a need for an apparatus and method which can effectively improve the lifetime of the wireless sensor network.